Project Summary There is growing concern about the possible health effects of positive sickle cell trait carrier status (SCT), with the National Collegiate Athletic Association now requiring testing of all Division I, II, and III athletes before they can play, and special training regimens if players do have SCT. Few large scale studies have been conducted, and epidemiologic investigations have not been conducted for this condition previously thought to be benign. We propose looking at mortality and end of life healthcare utilization for a cohort of approximately 140,000 persons identified in California?s Newborn Screening Program from 1990-2018 as having confirmed SCT. Using validated linking methodology, California Biobank Program (California Department of Public Health) will link these cases and three matched controls per case with California?s Vital Records Death files. These files include date of death and an underlying and three contributing causes of death. A secondary linkage, using Tracking California?s Dynamic Health Data Linkage tool, for those who died will add hospitalization and emergency department records for the last year of life, improving accuracy of specific cause of death for these persons. These data will be used to calculate all-cause mortality risk in the SCT population up to age 28 and to compare causes of death among the case and control populations. Publications, abstracts at major conferences, and health education materials for lay audiences will be developed and distributed with the results of these analyses.